In a recording tape cartridge so called a video tape cassette, there is provided a braking mechanism for preventing undesired rotation of a pair of tape reels when the video cassette is not in use. The braking mechanism usually comprises stopper members which are adapted to be detachably engaged with one of the teeth formed on the circumferential edge portion of the respective flanges of the tape reels and a spring member for biassing the stopper members towards the teeth portion of the tape reels when the video cassette is not in use. In the manufacturing process of such video tape cassettes, the tape reels with a magnetic recording tape and the braking mechanism are installed in positions in a bottom section of the video cassette and subsequently a top section is assembled with the bottom section. The bottom section and the top section are joined by screws in a known manner.
Conventionally, each element of the braking mechanism is prevented from disengagement by covering the braking mechanism by a part of the top section from above when the top section is assembled with the bottom section. However, the conventional way of preventing the disengagement of the braking mechanism as described above has many drawbacks as mentioned below:
(1) On an assembly line in a manufacturing process of the video cassettes before assembling of the top section, the stopper member of the braking mechanism readily flies upward in response to even a slight vibration, whereby the stopper member is displaced from position or the free end of the stopper member is unduly placed on the upper surface of the tape reel, causing a non operative state of the braking mechanism;
(2) Relative accuracy in terms of dimension and assembly between the top section, bottom section and the braking mechanism is severe, and errors in size of each of the components interact badly thereby resulting in difficulty in correct assembling of the braking mechanism. Therefore, a non operative state of the braking mechanism may easily occur;
(3) In order to cover the upper portion of the braking mechanism, the corresponding part of the top section facing the braking mechanism must have a configuration conforming to the upper portion of the braking mechanism, so the configuration of the corresponding part of the top section is necessarily complicated; and
(4) It is difficult to effect an automatic assembling of the braking mechanism in the bottom and top sections.